The Collaborative International Dictionary of English v.0.48:

Unbroken \Un*bro"ken\, a.
   Not broken; continuous; unsubdued; as, an unbroken colt.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Unbroken \Unbroken\
   See broken.

WordNet (r) 3.0 (2006):

unbroken
    adj 1: marked by continuous or uninterrupted extension in space
           or time or sequence; "cars in an unbroken procession";
           "the unbroken quiet of the afternoon" [ant: broken]
    2: not subdued or trained for service or use; "unbroken colts"
    3: (of farmland) not plowed; "unplowed fields"; "unbroken land"
       [syn: unplowed, unploughed, unbroken] [ant: ploughed,
       plowed]
    4: (especially of promises or contracts) not violated or
       disregarded; "unbroken promises"; "promises kept" [syn:
       unbroken, kept] [ant: broken, unkept]
    5: not broken; whole and intact; in one piece; "fortunately the
       other lens is unbroken" [ant: broken]

Moby Thesaurus II by Grady Ward, 1.0:

180 Moby Thesaurus words for "unbroken":
   accordant, alike, arrowlike, articulated, automatic, balanced,
   bright, catenated, ceaseless, chattering, concatenated, connected,
   consistent, consonant, constant, continual, continued, continuing,
   continuous, correspondent, cyclical, dead straight, direct, downy,
   endless, entire, equable, equal, even, featureless, flat, fresh,
   gapless, glabrate, glabrescent, glabrous, harmless, homogeneous,
   horizontal, immediate, immutable, in a line, incessant, intact,
   interminable, invariable, inviolate, irreversible, joined,
   jointless, leiotrichous, level, lineal, linear, linked,
   machine gun, measured, mechanical, methodic, mint, monolithic,
   monotonous, never-ending, nonstop, of a piece, one-way, ordered,
   orderly, oscillating, perennial, perfect, periodic, perpetual,
   persistent, plane, pristine, pulsating, rapid, rectilineal,
   rectilinear, recurrent, regular, repeated, repetitive, right,
   robotlike, round-the-clock, ruler-straight, running, scatheless,
   seamless, serried, smooth, smooth-shaven, smooth-textured, sound,
   stable, staccato, steadfast, steady, straight, straight-cut,
   straight-front, straight-side, straightaway, straightforward,
   straightway, streamlined, stuttering, suave, sustained, systematic,
   true, twenty-four-hour, unbending, unbent, unbowed, unbruised,
   unceasing, unchangeable, unchanged, unchanging, unconquered,
   uncurved, undamaged, undefaced, undeflected, undeformed,
   undemolished, undestroyed, undeviating, undifferentiated,
   undistorted, undiversified, unending, unenthralled, unfaded,
   ungoverned, unharmed, unhurt, unidirectional, uniform, unimpaired,
   uninjured, unintermitted, unintermittent, unintermitting,
   uninterrupted, unmaimed, unmangled, unmarked, unmarred, unquelled,
   unrelieved, unremitting, unrough, unroughened, unruffled,
   unscarred, unscathed, unscratched, unshattered, unspoiled,
   unstopped, unsubdued, unsubject, unswerving, untamed, untorn,
   untouched, unturned, unvanquished, unvaried, unvarying, unwithered,
   unworn, upright, vertical, vibrating, virgin